A cutter ramp is a physical ramp or angled feature, located at the intersection of a machined flange pocket, that is created by the act of cutting an acute angle wall with a cylindrical cutting tool. FIG. 1 is a cross sectional view of a flange joint 100 as designed and modeled without a cutter ramp curve. Flange joint 100 includes a flanged component or part 102 and a component 104, which is attached to flanged part 102 with a fastener 106. Flanged part 102 includes a web face (or floor) 108 and an acute angle wall (or flange face) 110 extending from web face 108. The junction of web face 108 and acute angle wall 110 is modeled as a simple fillet having a tangent point 112 located on the face of acute angle wall 110. In a three dimensional model, this tangent point corresponds to a flange tangency edge or curve. The distance (Cm) between tangent point 112 and the longitudinal axis of fastener 106 represents the fastener clearance as modeled.
FIG. 2 is a cross sectional view of a flange joint 200 modeled as described above in connection with FIG. 1, but machined in accordance with practical manufacturing techniques that produce a cutter ramp. Flange joint 200 includes a flanged component or part 202 and a component 204, which is attached to flanged part 202 with a fastener 206. Flange 202 includes a web face (or floor) 208 and an acute angle wall (or flange face) 210 extending from web face 208. Flanged part 202 is machined using a cutter 212, which is a cylindrical tool having a substantially flat tip with slightly radiused edges. As shown in FIG. 2, cutter 212 forms a cutter ramp 214 in the inner pocket of flange 202. Formation of cutter ramp 214 results in additional solid material remaining in the inner pocket of flanged part 202 in comparison to the ideal fillet modeled in FIG. 1. Notably, since flange joint 200 was modeled as flange joint 100, cutter ramp 214 interferes with the modeled location of fastener 206. This interference point is identified by reference number 216 in FIG. 2.
As illustrated by FIG. 1 and FIG. 2, the design of fastened joints can be hindered by the inability to economically model a cutter ramp in machined parts. For example, the absence of a cutter ramp on a CAD model can lead to the improper location of fastener patterns, typically manifested as short fastener clearances to edges. This condition is either corrected by re-design upon discovery or by analytical verification that the condition can be accepted in the final design. Both of these solutions can be time consuming and expensive to implement.
Accordingly, it is desirable to have an automated software tool that is capable of quickly modeling cutter ramps and cutter ramp tangent curves in machined parts. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.